In audio communications (e.g., voice communications), excessive amounts of surrounding and/or background noise can interfere with intended exchanges of information and data between participants. Surrounding and/or background noise includes noise introduced from a number of sources, some of the more common of which include computers, fans, microphones, and office equipment. Accordingly, noise suppression techniques are sometimes implemented to reduce or remove such noise from audio signals during communication sessions.
When multiple input channels (e.g., microphones) are involved in audio communications, noise suppression processing becomes more complex. Conventional approaches to multi-channel noise suppression focus on a beam-forming component (e.g., a combined signal), which is a time-delayed sum of the two (or more) input channel/microphone signals. These conventional approaches use this combined input signal as the basis for noise estimation and speech enhancement processes that form part of the overall noise suppression. A problem with these conventional approaches is that the beam-forming may not be effective. For example, if a user moves around, or the room filter (and hence time-delays) are difficult to estimate, then relying on the beam-formed signal only is not effective in reducing noise.